1. Field of the Invention
The present invention relates to a storage device in which plate-like members such as printed boards or pallets for component supply are stored vertically over a plurality of tiers in such a manner that the plate-like members can be loaded and unloaded to/from the storage device.
2. Background Art
Conventional examples of such storage devices include, for instance, component supply devices such as the one disclosed in Japanese Patent Application Publication No. 2009-147197. This component supply device supplies package-type electronic components (hereafter simply referred to as components) such as quad flat packages (QFPs) in a state where the components are stored in trays.
The component supply device comprises: a box-shaped housing; a stocker, supported on the inner sides of the housing, and in which pallets (plate-like members), having respective trays placed thereon, are stored vertically over a plurality of tiers; a stocker lifting and lowering device that lifts and lowers the stocker within the housing; and a drawing device that draws pallets out of the stocker. The housing is provided with a drawing port for drawing the pallets out at a predetermined height position, and the drawing device is disposed at a position in front of the drawing port. In this component supply device, components are supplied through lifting and lowering of the stocker, as a result of which a pallet having a desired component (tray) placed thereon stands opposite the drawing port, and, in this state, the pallet is drawn out by the drawing device.
In the above conventional component supply device (storage device), it is necessary to lift and lower the stocker in which the plurality of pallets is stored, as described above. The housing and so forth have to be higher rigid, and a substantial driving force is required, in order to stably lift and lower the comparatively heavy stocker. Accordingly, the component supply device has the drawbacks of being comparatively large and heavy, as well as costly. However, such component supply devices are extensively used thanks to the advantages that they afford, namely the fact that pallets can be loaded and unloaded at a specified height position, and that all movable portions are accommodated within the housing. Accordingly, it would be desirable to overcome the above drawbacks.